1. Field of the Invention
The invention relates to a horizontal-axis electrical machine having a stator laminate core which is arranged in a housing which is split horizontally and is stiffened by housing formers, which stator laminate core is clamped by means of fastening wedges, which are distributed over its circumference, in supporting rings, which are arranged orthogonally to the machine longitudinal axis, are spaced apart from one another and are connected on their external circumference, via fastening parts, to the housing lower part of the machine, which fastening parts have azimuthal fastening plates which run symmetrically with respect to the vertical plane of symmetry of the machine.
The invention at the same time makes reference to a prior art as results, for example, from CH-PS 665,507 or U.S. Pat. No. 4,663,553.
2. Discussion of Background
In the case of gas-cooled electrical machines over the entire power range, large axial and radial expansions occur in the stator laminate core which must be transmitted to the housing distributed as uniformly as possible.
In the case of the air-cooled turbogenerator which is known from CH-PS 665,507, this is done by lateral suspension of the stator laminate core by means of supporting rings which are arranged parallel, are at right angles to the axis of the electrical machine and are spaced apart from one another. In order to keep vibrations and thermal stresses which occur during the operating mode of the electrical machine as small as possible, the supporting rings are connected to the housing lower part by means of fastening parts, via extensions which run vertically in a straight line, on both sides in two regions of their vertical plane of symmetry. By far the greater majority of the circumference of the supporting plates is spaced apart from the housing upper part and housing lower part. The stator laminate core is clamped in the supporting plates by means of fastening wedges which are distributed uniformly over its entire circumference. The fastening parts comprise fastening plates which are in each case welded to the extensions of the supporting plates, as well as horizontal-axis tube elements which are welded both to the fastening plates and the housing lower part. This fastening of the stator laminate core allows simple assembly, easy accessibility to the structural parts which are to be welded and ensures good quality of the welded seams.
In the case of large air-cooled turbogenerators, the laminate core vibrations at twice the frequency and the sound emissions resulting from this become very large. However, as the size of the machine increases, the stresses in the components and welded seams of the connecting points to the housing also increase. This can result in so-called low-cycle fatigue cracks as a consequence of laminate core vibrations and thermal alternating stresses of the start/stop cycles.